Footwear article and method for facilitating walking

ABSTRACT

Rheumatoid arthritic patients and others are enabled to walk by means of an article of footwear which has an un-bendable platform provided on its upper surface with padding material and provided on its lower surface with a tread having heel and sole portions. The tread surface assumes a stable non-rocking condition when at rest on a flat ground surface. The heel portion has the entirety of its ground-contacting surface located forwardly of the anatomical rear edge of the patient&#39;&#39;s foot to reduce impact loading of the forefoot at the foot flat portion of gait; and, the sole portion is inclined forwardly and upwardly to reduce the shear forces on the patient&#39;&#39;s foot during the push-off portion of gait.

United States Patent 1 Barrett, Jr.

[ FOOTWEAR ARTICLE AND METHOD FOR FACILITATING WALKING [76] Inventor:John P. Barrett, Jr., 40 Fairfax St.,

Burlington, Mass. 01803 22 Filed: June 23,1972 21 App]. No.: 265,913

. [52] US. Cl. 36111.5 [51] Int. Cl. A43b 3/12 [58] Field of Search36/25 R, 7.5, 7.6,

[56] References Cited UNITED STATES PATENTS 2,519,458 8/1950 Hall 36/7.52,825,153 3/1958 Fab'rizio 36/2.5 R 3,472,508 10/1969 Baker et a].36/115 Junel9, 1973 Primary Examiner-Patrick D. Lawson Att0rney-FrancisCl Browne, Joseph A. DeGrandi and Richard G. Kline [57] ABSTRACTRheumatoid arthritic patients and others are enabled to walk by means ofan article of footwear which has an un-bendable platform provided on itsupper surface with padding material and provided on its'lower surfacewith a tread having heel andsole portions. The tread surface assumes astable non-rocking condition when at rest on a flat ground surface. Theheel portion has the entirety of its ground-contacting surface locatedforwardly of the anatomical rear edge of the patient's foot to reduceimpact loading of the forefoot at the foot flat portion of gait; and,the sole portion is inclined forwardly and upwardly to reduce the shearforces on the patient's foot during the push-off portion of gait.

14 Claims, 5 Drawing Figures FOOTWEAR ARTKCLE AND METHOD FORFNCHLITATING WALKING This invention is related to the structure and useof an article of footwear primarily intended for rheumatoid arthriticpatients and others who have extreme difficulty in walking as a resultof deformities or sensitivity which renders the foot incapable offunctioning in a normal manner.

Normal walking involves a gait having two principal phases, a swingphase when the foot is moving forwardly and is not supported by theground surface, and a stance phase during which the foot is supported bythe ground surface. The stance phase may be further subdivided into theheel strike portion when the heel of the foot or shoe initially contactsthe ground surface, a foot flat portion during which the weight isshared by the heel and the forefoot and the push-off or toe-off portionduring which the weight and pressure are borne by the forefoot and thefoot pushes rearwardly to provide the forward thrust of the body.Throughout the stance phase, the foot is constantly undergoing a changein orientation, with a general rocking motion producing the transitionfrom the heel strike portion to the foot flat portion, and then from thefoot flat portion to the push-off portion.

For various reasons, many medical patients are unable to walk in anormal fashion, due to deformities of the foot, paralysis or extremesensitivity of the forces created during a normal gait. Patients havingrheumatoid arthritis, leprosy and severe diabetes are illustrative. Forexample, arthritic patients have painful prominent callosities on thesole of the foot, deformities which create a functionally short foot andsensitivities which prevent the normal exertion of pressure by the toes.This requires such patients to perform the pushoff portion of gait withthe ball of the foot. This invention is intended to permit such personsto walk and/or to reduce the degree of pain required to walk. A numberof features of the present invention contribute to its performance.

According to one feature of the invention, a rigid and unbendableplatform for the foot is provided on its upper surface with a paddingmaterial which minimizes concentrations of pressure and deforms underthe pressure of the foot to provide a foot-surrounding ridge to preventshifting of the foot during walking.

The invention is also intended to promote proper functioning of theforefoot mechanics of some patients, by avoiding any lateralconstriction of the midtarsal area and permitting the heel to lift offthe platform padding during the transition form foot flat to push-offportion of gait. This latter feature permits many patients to use theproper metatarsal motion since the heel must rise to cause the heads ofthe metatarsals to come in proper sequence and shift the pressureprofile from lateral to medial. Means are also provided for biasing theheel portion of the wearers foot against the padding on the platform,which is particularly important with patients who are unable to exertdownward pressure with their toes to restore the heel into contact withthe pad din A nother feature involves a novel combination of known soleand heel structures. The sole tread surface is inclined forwardly andupwardly to permit a patient to roll toward the push-off, therebyreducing the extent of shearing forces between the foot and the articleof footwear. The rearwardmost portion of the heel is forwardly displacedfrom its usual position in order to reduce impact loading of theforefoot during the transition from the heel strike to the foot flatportion gait.

According to the disclosed embodiment of the invention, the patient isalso permitted to stand still with ease since the tread surface isconstructed to assume a stable non-rocking orientation at the foot flatportion of gait, unlike some prior devices which have had arcuatesurfaces extending continuously throughout the length of the heel andsole area.

The preferred embodiment of the invention also minimizes discomfort onthe upper surface of the foot during the swing phase of gait when thearticle of footwear is supported by the foot. This advantage is realizedby placing the forefoot-retaining strap immediately behind the extremelypressure-sensitive points at the base of the great toe and the base ofthe fifth toe. This feature is particularly important in footweardesigned for pa tients whose feet are extremely sensitive to pain.

For a more complete understanding of the invention, a preferredembodiment is shown in the accompanying drawings wherein FIG. 1 is aside elevation thereof, showing the position of a foot supported on thedevice;

FIG. 2 is a plan view of the device which also illustrates the principalareas of pressure of a typical arthritic patient; and,

FIGS. 3-5 illustrate the device of this invention at the three principalportions of the stance phase of gait.

Referring to FIG. 1, it will be seen that the foot of a patient is atthe location shown in broken lines at 2 where it rests on a layer ofpadding material 4 located on the upper surface of a rigid platform core6. The areas of maximum pressure of one arthritic patients foot aredesignated by the broken lines 34. On the undersurface of the platformcore 6 is the bottom of the sandal which is preferably made of cushioncrepe and provides a tread surface having a sole portion 8 and a heelportion 10. Various materials may be used in the manufacture of thecomponents of the device, but it is important that its overall structurebe substantially unbendable.

The wearers heel is retained on the device by means of a loop 12 whichhas a buckle 14. The loop 12 encircles the foot above the instep, in thevicinity of the ankle. A strap 16 having an elastic or gore portion 18connects the loop 12 with the platform so that the elastic 18 biases thewearer's heel against the padding material 4 of the platform. Thebiasing force is insufficient to hold theheel in contact with thepadding material 4 during the latter portions of the stance phase ofgait. The heel is permitted to lift off the padding material by at leastabout one-half inch as the elastic 18 extends, thereby permitting normalfunctioning of the forefoot mechanics in the midtarsal and metatarsalregions. An optimum distance of lift-off is aboutthree-quarters of aninch. The amount of force exerted by the elastic may be adjusted to somedegree by changing the size of the loop 12, thereby changing itselevation and the amount of tension in the elastic 18.

The forefoot is held against the padding 4 of the platfonn by means suchas the straps 20 and 22 which have buckles 24 and 26. With some patientswho have unusually sensitive feet, it is important that the straps 20and 22 be located rearwardly of the extremely pressure-sensitiveportions of the forefoot, specifically the base of the great toe and thebase of the fifth toe. Furthermore, it is important that the straps 20and 22 are spaced transversely of the foot so they do not laterallyconstrict the foot to interfere with the normal distribution of weightand pressure in the midtarsal region.

The particular materials used for making products according to theinvention are not critical. The padding 4 may be conventional foamrubber, a thermolabile polyethylene foam material used in orthopedicsand sold under the trademark Plastazote or generic polyethylene foampreferably providing a durometer reading of about 57-61 Shore. Thislatter material is particularly desirable since, after a few weeks, itwill bottomout to conform to the foot of the wearer so that the footwill be surrounded by a ridge of padding which will prevent shifting ofthe foot on the upper surface of the sandal. In this condition, thepadding does not act as a resilient cushion, but serves to avoidpressure concentrations by conforming to the sole of the foot.

As will be seen in FIG. 1, the heel has a downwardly and forwardlyinclined rear surface 28 which serves, in a previously-known matter, tolocate the entirety of the sandal heel and its rearwardmostground-contacting edge 30 of the heel at least one-eighth to one-quarterinch forward of the anatomical rear edge 32 of the wearers foot. Thisserves to shorten the steps of the patient, locate the impact-receivingpoint of the heel closer to the center of the pressure-sustaining areaof the wearers heel and to shorten the heel lever to reduce the force ofimpact created when the sole portion 8 strikes the ground surface at thefoot flat portion of gait. This latter operation may also be achieved byproviding a slight upward and rearward inclination of the tread surfaceof the heel portion so that the heel will rock from its forward edge 32into the foot flat portion of gait.

The sole portion 8 is inclined upwardly and forwardly, preferably in anarcuate fashion known in the prior art, so that the transition from thefoot flat to the push-off portion of gait may occur gradually withoutthe necessity for excessive shearing forces between the foot and thepadding material 4 at the point of push-off. The sole 8 has its rearwardportion located approximately in the plane of the undersurface of theheel portion 10 so that a wearer may stand still with the longitudinallyspaced points on the sole and heel simultaneously contacting the groundsurface. The weight is then distributed on the sole and heel portions ofthe device. Accordingly, the wearer is not required to balance himselfon an arcuate tread surface which would produce an unstable,uncomfortable rocking of the sandal and foot.

The normal use of the invention is shown in FIGS. 3, 4 and 5, with FIG.3 illustrating the heel strike portion of gait where the rearwardmostground-contacting edge 30 of the tread surface strikes the ground tocreate upward pressures on the foot in the heel area surrounded by thebroken lines 34 in FIG. 2.

Continuation of the normal gait causes the tread portion to pivotdownwardly on the rear edge 30 until the foot flat portion of gait isreached as shown in FIG. 4. This is also the position assumed by thefoot and sandal when the patient is standing still. At this point, theweight is supported by the forefoot and heel.

Next, the foot rocks forwardly on the arcuate undersurface of the soleportion 8. During this rocking movement, the forefoot mechanics are atwork with the usual midtarsal and metatarsal movement occurring for manypatients. At this point, the lifting of the wearers heel extends theelastic 18 so that the foot will lift off the padding material 4 topermit the proper functioning of the forefoot mechanics. The ability ofthe sole portion to rock forwardly reduces the amount of shearing forcerequired at the push-off portion of gait and thereby further avoids orminimizes the amount of discomfiture to which the patient is subjected.

The disclosed sandal has been found to perform acadence-monitoringfunction which reduces the amount of pain experienced by the patient.The steps are shorter and less frequent, so there is a reduction invelocity which also minimizes the forces of impact and shear producedduring the stance phase of gait.

Those skilled in the art will realize that a wide variety of materialsmay be used in practicing the invention and that it is desirable todesign the sandal or other article of footwear according to measurementsand analy-- sis of the anatomical and functional characteristics of theindividual patients feet. In some instances, only selected featuresdescribed above will be required for the 1. An article of footwear forpatients who have functionally foreshortened feet, comprising, g

a ground-contacting base including a tread surface which has a soleportion and a heel portion which are relatively immovable with respectto each other, said sole portion being inclined forwardly upward toreduce the shear forces on a patients foot during push off,

said heel portion having its rearwardmost groundcontacting portionlocated forwardly of the anatomical rear portion of the patients foot toreduce impact loading of the forefoot at the foot flat portion of gait,

a foot-supporting means above the base for conforming to the shape ofthe patients foot, and,

a forefoot retaining means constructed to allow maximum midtarsalmotion,

heel retaining means for laterally positioning the patients heel on thefoot-supporting means while permitting at least a one-half inchdisplacement of the patients heel from the foot supporting means duringthe push-ofi' portion of the patients gait.

2. An article of footwear according to claim 1 wherein the heelretaining means includes a generally horizontal loop for encircling thepatient's foot above the instep and means for connecting said loop tosaid base.

3. An article of footwear according to claim 2 wherein the means forconnecting said loop to said base is elastic.

4. An article of footwear according to claim 1 wherein the footsupporting means is a permanently deformable pad means which extendslaterally beyond a patients foot to provide a ridge which surrounds thefoot and prevents lateral shifting thereof.

5. An article of footwear according to claim 4 wherein the deformablepad means is of foam material.

6. An article .of footwear according to claim 1 wherein the treadsurface has portions which are longineously contact a flat tudinallyspaced apart and are positioned to simultaground surface, therebyassuming a stable non-rocking position when a patient is standing still.

7. An article of footwear according to claim 1 wherein the forefootretaining means includes strap means located to overlie a patients footexclusively rearwardly of the toes to avoid discomfort to the foot'during that portion of the gait when the foot is raised and the articleof footwear is supported by the foot.

An article of footwear according to claim 7 wherein the opposite ends ofthe strap are spaced transversely from the patients foot to avoidlateral constriction of the foot and to maximize the distribution ofpressure on the underside of the foot during the pushoff portion ofstance phase of gait.

9. A method of facilitating walking by patients with highly sensitive orfunctionally foreshortened feet, said method being performed byattaching to the foot an article of footwear which has a substantiallyunbendable platform provided on its upper surface with a layer ofpadding material and provided on its lower surface with a tread surfacewhich has a sole portion and a heel portion, said tread surface assuminga stable non-rocking condition when at rest on a flat ground surface,said sole portion being inclined forwardly and upwardly to reduce theshear forces on a patients foot during the toe-off portion of gait, saidheel portion having the entirety of its ground-contacting surfacelocated forwardly of the anatomical rear portion of the patients foot toreduce impact loading of the forefoot at the foot flat portion of gait.

10. The method of claim 9 wherein the article of footwear is attached tothe forepart of the foot by passing a strap over the forepart of thefoot rearwardly of the toes without laterally constricting the foot,thereby providing for maximum midtarsal motion during the toe-offportion of gait.

11. The method of claim 1 wherein the foot is laterally confined by thatportion of the padding material which is uncompressed and lies laterallyof the foot.

12. The method of claim 1 wherein the article of footwear is attached tothe foot by forming a loop around the foot in the vicinity of the ankle,and resiliently biasing the loop toward the platform with a force havinga magnitude such that the heel will lift off the upper surface of theplatform only during the toe-off portion of gait.

13. The method of claim 12 wherein the article of footwear is attachedto the forepart of the foot by passing a strap over the forepart of thefoot rearwardly of the toes without laterally constricting the foot,thereby providing for maximum midtarsal motion during the toe-offportion of gait.

14. The method of claim 13 wherein the foot is laterally confined bythat portion of the padding material which is uncompressed and lieslaterally of the foot.

1. An article of footwear for patients who have functionallyforeshortened feet, comprising, a ground-contacting base including atread surface which has a sole portion and a heel portion which arerelatively immovable with respect to each other, said sole portion beinginclined forwardly upward to reduce the shear forces on a patient''sfoot during push off, said heel portion having its rearwardmostground-contacting portion located forwardly of the anatomical rearportion of the patient''s foot to reduce impact loading of the forefootat the foot flat portion of gait, a foot-supporting means above the basefor conforming to the shape of the patient''s foot, and, a forefootretaining means constructed to allow maximum midtarsal motion, heelretaining means for laterally positioning the patient''s heel on thefoot-supporting means while permitting at least a one-half inchdisplacement of the patient''s heel from the foot supporting meansduring the push-off portion of the patient''s gait.
 2. An article offootwear according to claim 1 wherein the heel retaining means includesa generally horizontal loop for encircling the patient''s foot above theinstep and means for connecting said loop to said base.
 3. An article offootwear according to claim 2 wherein the means for connecting said loopto said base is elastic.
 4. An article of footwear according to claim 1wherein the foot supporting means is a permanently deformable pad meanswhich extends laterally beyond a patient''s foot to provide a ridgewhich surrounds the foot and prevents lateral shifting thereof.
 5. Anarticle of footwear according to claim 4 wherein the deformable padmeans is of foam material.
 6. An article of footwear according to claim1 wherein the tread surface has portions which are longitudinally spacedapart and are positioned to simultaneously contact a flat groundsurface, thereby assuming a stable non-rocking position when a patientis standing still.
 7. An article of footwear according to claim 1wherein the forefoot retaining means includes strap means located tooverlie a patient''s foot exclusively rearwardly of the toes to avoiddiscomfort to the foot during that portion of the gait when the foot israised and the article of footwear is supported by the foot.
 8. Anarticle of footwear according to claim 7 wherein the opposite ends ofthe strap are spaced transversely from the patient''s foot to avoidlateral constriction of the foot and to maximize the distribution ofpressure on the underside of the foot during the push-off portion ofstance phase of gait.
 9. A method of facilitating walking by patientswith highly sensitive or functionally foreshortened feet, said methodbeing performed by attaching to the foot an article of footwear whichhas a substantially unbendable platform provided on its upper surfacewith a layer of padding material and provided on its lower surface witha tread surface which has a sole portion and a heel portion, said treadsurface assuming a stable non-rocking condition when at rest on a flatground surface, said sole portion being inclined forwardly and upwardlyto reduce the shear forces on a patient''s foot during the toe-offportion of gait, said heel portion having the entirety of itsground-contacting surface located forwardly of the anatomical rearportion of the patient''s foot to reduce impact loading of the forefootat the foot flat portion of gait.
 10. The method of claim 9 wherein thearticle of footwear is attached to the forepart of the foot by passing astrap over the forepart of the foot rearwardly of the toes withoutlaterally constricting the foot, thereby providing for maximum midtarsalmotion during the toe-off portion of gait.
 11. The method of claim 1wherein the foot is laterally confined by that portion of the paddingmaterial which is uncompressed and lies laterally of the foot.
 12. Themethod of claim 1 wherein the article of footwear is attached to thefoot by forming a loop around the foot in the vicinity of the ankle, andresiliently biasing the loop toward the platform with a force having amagnitude such that the heel will lift off the upper surface of theplatform only during the toe-off portion of gait.
 13. The method ofclaim 12 wherein the article of footwear is attached to the forepart ofthe foot by passing a strap over the forepart of the foot rearwardly ofthe toes without laterally constricting the foot, thereby providing formaximum midtarsal motion during the toe-off portion of gait.
 14. Themethod of claim 13 wherein the foot is laterally confined by thatportion of the padding material which is uncompressed and lies laterallyof the foot.